Paris, Nicole: To Fight on The Simple Life 5?

E! Entertainment Television has ordered a fifth season of the reality series The Simple Life, E! Networks president and CEO Ted Harbert announced at the Television Critics Association press tour on Tuesday.

But this time, stars and best friends-turned-archenemies Paris Hilton and Nicole Richie might not be filmed separately, as they were for season four, The Simple Life: 'Til Death Do Us Part.

"I don't have any control over whether they'll be friends by next season," Harbert tells PEOPLE. "We need to talk about the best thing to do for the show, and I'm not sure shooting them separately again is the best thing for the show."

On the most recent season, Hilton, 25, and Richie, 24, were shown trying to run the households of regular families – but the two did not share any screen time.

Still, the show was a hit for E! – its June 6 premiere drew triple the cable net's average viewers. "We pulled off a difficult thing this year, but frankly we got away with it," says Harbert. "We can't do that again."

And hopefully, when the feuding heiresses are forced to interact, sparks will fly, says an insider. "They want to give the viewers what they want, and what the viewers want is to see Paris and Nicole together, fighting," says the source.